Going backward through your post to respond.
1) I did not claim the elect or firstborn are restricted to the levites or priests. Rather, I was asking if the atonement blood was restricted to them. For in the presentation that all believers are the elect and the priests, then if the blood of the OT type were true to the picture, the levites and priests would be the only beneficiaries.
2) The point of going through the long post on Isaiah was to demonstrate that more often the selection of a passage to support a line of thinking should actually be supported by the context of that passage. So, I attempted in a very brief manner to show how the selection you posted was actually used in the context.
3) Perhaps it may be good to reflect on some questions. Offered more for rhetorical reflection, then of proving one side of the argument or the other.
Was those chosen and taken out of Egypt ALL Jews? Or was there a mixed multitude?
When the tabernacle offerings were instituted, were they for the multitude that came out of Egypt (including the mixed multitude) or for the Jews, only?
When the atonement offering was made, were other than Jews included?
Were all Jews believers when the atonement offerings were made?
What were the Jews called by God, and did this include those converted who were not blood related to the nation?
When strangers, slaves, or travelers were among the Jews, did not the blood cover them, too?
When Christ shed his blood, why present it as restricted to the believers, when the Scriptures present the believers are chosen by God, and not a single time is blood presented but as to ALL - all the world, all ungodly, ...?
How can the whole world be held accountable for the rejection based on lack of belief, if the blood of that promise was not shed for them?
Can a single soul stand before the final judgment and be able to proclaim, "How can I not be excused? You shed no blood on my behalf? You only shed it for others, and that supposed to be just?"
Ok, enough of the rhetorical questions.
I want to compliment you on presenting the Scriptures with your arguments. It makes for good foundational conversation!
I would consider that we agree on much, perhaps more than either of us would admit in the sharpness of discerning difference within exchanges such as this thread.